The captain has ultimate responsibility is often quoted. This is responsibility for decisions made from information and observations which he is reasonably expected to acquire from the machinery and environment.
Surely when a Clearance is issued, based on information which the captain does not have, responsibility is taken for the captain's actions. Any override would only be because of conflicting data.
An interesting situation arises when connected to a tug during pushback into a busy taxyway, especially when English is not the first language.